How to fine-tuning your TT position during lockdown?
So it’s easy–you just do a bike fit and you’re all set up. Right?!
Not always.
I’ve been writing about the importance of saddle hight and how much it could affect your performance. This time I will give an example how fast and how easy that could be if you have popper tools and some basic (or just above) knowledge.
In times of COVID-19, when options of seeing your athletes on the bike are very limited, data is serving a double purpose–it lets you see what really happens even if you cannot see your athlete riding.
I remember when back in the days I fitted my bike just by using a plumb bob, to see my “knee over pedal” and just by placing my heel on the pedal with fully extended leg. That was the premise of how bike fit worked about 15 years ago.
Now when we have technology like Leomo at our disposal, it’s far more complicated you may think. But I would argue it’s quite the opposite. Yes, there is much more data involved and by using it you are cutting out a lot of guesswork which is a considerable part of the fitting model I described before. Therefore, using Leomo we can now quantify what athlete is feeling on the bike and find a cause-and-effect relationship.
My subject in this example is above average cyclist and a capable runner. His aim is to compete in TT’s and do IM distances. As he recently bought a TT bike and (of course) was complaining about how uncomfortably it feels to be in his aero position and how he is loosing power. So we agreed to use Leomo to fine-tune his position.
Athlete’s in-season FTP is about 370w, which is about 4.8w/kg for him.
Athlete’s 10km pace is about 4:10 and half marathon about 5:30.
Measuring the baseline
In order to understand “where” he is with numbers, we did initial test just to collect the data. This time we’ll be looking only at his Dead Spot Score (DSS)*
*Dead Spot Scores (DSS) pinpoint the magnitude and locations where pedaling velocities lack smoothness along the left and right pedaling cycle.
Lack of smoothness is a secondary symptom of sub-optimal pedaling motions.
Looking at the right and left DSS values provides insight to the left/right movement imbalances.
As you can see by the results–not awful but not good either. For somebody with such a good overall power numbers it would not be wise to “waist” his energy on sub-optimal pedal stroke.
DSS score of 8.1 on his left leg is high compared to his 0.8 on his right leg. I already know that he has some asymmetry, which shows in DSS score.
I need to stress that DSS is NOT your typical L/R balance you can see from your power meter. Leomo is measuring movement of your leg every hundredth of a second, not just dividing your pedal stroke in half.
As you can see in screenshot from TrainingPeaks, his L/R balance is 51/49 which does not show any abnormalities or problems.
Testing different position
In order to cut the guesswork and any bias towards either athlete’s “ideal” position (which usually is just the way one looks in the photos anyway) or my bias as well, I use a very simple way how to test things. I throw a bunch of things against the wall and see what sticks. Simplifying it down I believe is a big part of almost any process at least at the beginning because it lets you see cause and effect of any adjustments you make.
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I use a simple matrix of measurements, where I use a current setup as a starting point of measurements, and then move saddle high and for/aft in whatever steps you like. I start with big steps, about 2cm, so we can distinctly see what works and what doesn’t. And the for athlete it’s quite easy because position changes are quite pronounced, so it’s much easier to have feedback on the effect of those changes.
In this manner you can test 9 position in one training session. Doing this indoor is easier just because of the ease with what you can do any changes to your bike position. You always have your tools at your disposal and don’t have to worry about traffic or potholes. Yes, position indoors could differ from the one you will be holding when riding outside, but this is a topic for another blog post.
This is how one such session looks like. It takes about 1h50min with all the adjustments, so not very time-consuming given that he tested 9 different positions.
Lap number six clearly provided the best results despite having I would say big position changes on his bike.
DSS for both legs decreased substantially from 8.1 to 0.5 on his left leg and from 0.8 to 0.2 on his right. So he went lower and further ahead.
Not bad to have such significant changes from only one transgression!
Then we repeated the same testing protocol but with a new baseline (our values from Lap number 6) and changed adjustment step from 2cm to 0.5cm. This will allow to fine-tune the results from the first session.
Although 0.5cm may seem not that significant, I already answered why it’s not true in my previous Leomo case study. Here it provided almost as significant as in that case.
It’s not that pronounced as with 2cm changes, which should be logical, but it still gave quite a good idea which should be his new baseline. Funny enough, this time it was lap number 6 as well.
Although DSS score didn’t change significantly, but Pelvic Rotation went further down from 6.3° to 5.6°. This means he is more planted and more stable in his saddle.
Next we’ll be adjusting his front end. This will be more tricky and more time-consuming, but it will happen in the same manner we did it with his saddle high.
Most probably I’ll do some short write up on this process as well so it gives you a full picture of what goes into fine-tuning one’s position on TT bike during lockdown.
Be safe and train smart!
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Author,
JANIS MUSINS
Train2Win Endurance Coaching Head Coach
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